Merge branch 't/releases_branch'

	18d2c3 Remove all release tarballs from the master branch.
	f82ac2 web: Rename tarball download directory.

Was cooking since 2012-07-28, tested also on athcx.

diff --cc NEWS
index 84d68d82835f79a7156a17d1a661bc37e483ca54,84d68d82835f79a7156a17d1a661bc37e483ca54..65a5ca44dde9a92ac8e0b61ecf92397d1e19c933
--- 1/NEWS
--- 2/NEWS
+++ b/NEWS
@@@ -2,6 -2,6 +2,10 @@@
  0.?.? (to be announced) "volatile relativity"
  ---------------------------------------------
  
++      - The "versions" directory has been removed from the master
++        branch. The tarballs of the old releases are now available
++        in the new "releases" branch.
++
  --------------------------------------
  0.4.11 (2012-07-20) "mutual diversity"
  --------------------------------------